Conductive connecting terminals are extensively applied on various occasions and perform a basic function of transmitting an electronic signal/current. There are other requirements for conductive connecting terminals on some special application occasions, for example, sealing requirement. For example, an engine or gearbox of a motor vehicle uses a conductive connecting terminal passing through a cylinder body. This is a very severe application environment. A high temperature above 150° C. frequently reached in the cylinder, splash of engine oil and vibration caused by the engine itself and a road surface imposes very high requirements for the sealing performance of the conductive connecting terminal. Conventionally, both ends of the conductive connecting terminal are connected by a lead wire wrapped by an insulating skin. Although an outer circumference of the insulating skin may be sealed with a sealing member, since the lead wire employs multiple strands of copper filaments and gaps exist between copper filaments, leakage of oil probably occurs in the lead wire through capillary phenomenon.
Attempts have been made to use a connecting terminal 1 shown in FIG. 1 to solve the above problem. The connecting terminal 1 is formed from an alloy material by the machining of a turning machine, with one end 10 being formed in a barrel shape to connect the lead wire, the other end 20 mating with a female member, and an intermediate section 30 formed with a radially-raised protrusion 35 to form sealing. However, it is found that this connecting terminal at least has the following drawbacks:
First, in order to form the sealing protrusion 35 at the intermediate section, the conductive connecting terminal 1 must be formed by the machining of a turning machine and formed for a single time, which causes the manufacture cost of the connecting terminal 1 is high.
Secondly, only a tip 20 of the connecting terminal 1 mating with the female member needs to be applied a plated layer and the remaining sections needn't be applied a plated layer. However, it is found in actual application that the machined member has to be applied a plated layer on an entire surface, i.e., the whole of the connecting terminal is placed in an electroplating liquid and it is very difficult to perform selective plating, which makes the plating cost unnecessarily increased. A very high cost of the plated layer further makes the manufacture cost of the connecting terminal even higher. This drawback is particularly striking when a large number of connecting terminals need to be applied a plated layer.
Moreover, one end 10 of the connecting lead wire of the connecting terminal 1 can only match wires with limited wire diameters and cannot match wires with various wire diameters. This requires connecting terminals of different specifications upon connection with lead wires with different wire diameters.
Therefore, it is desirable to provide a new conductive connecting terminal to overcome the above-mentioned various drawbacks and shortcomings of conventional conductive connecting terminals.